ANALYSIS OF TRUSSED TOWER STRUCTURES BY NON-CLASSICAL ENERGY METHOD

A new method------the non-classical energy method basedon semi-continuity and semi-discreteness idea-is proposed in this paper for the static and dynamic analysis of built-up space trussed tower structures that are applied in engineering very often, e. g. TV tower, transmission line tower, boring tower and sea platform tower.The global; tower structure is treated as a non-classiccal beam with variable cross-section in which the actions of tension, extrusion, shear and bending are considered. The displacements of any node of the structurecan be described by the four generalized displacements metioned above. Whereby, the strains and internal forces of each member and the corresponding potential energy, kinetic energy and external forces work can be considered in detail. A set of linear algebraic equations is obtained based on the variational principle of potential energy. The number of unknowns is only related to the undetermined coeffici ents in the trial functions of the four generalized displacements, irrelated to the number of truss members and nodes, the shape of cross-sections and the height of the tower. Usually, the number of unknowns is only about 10-30, much less than that referring by means of finite element method. In the meantime, the present method can cope with various trussed towers including the effects of additional installation conveniently.The numerical calculation results of TV tower and sea platform tower are given. They indicate that the present method can be run on a microcomputerand its computer program is very simple and can be applied widely.